lib/DSK.rb in dsktool-0.1.4 vs lib/DSK.rb in dsktool-0.1.5

@@ -5,20 +5,25 @@
 #
 # For manipulating DSK files, as created by ADT (http://adt.berlios.de) and ADTPRo (http://adtpro.sourceforge.net)
 # used by many Apple 2 emulators.
 #
 class DSK
-
+
+	#does this filename have a suitable extension?
+	def DSK.is_dsk_file?(filename)
+		!(filename.upcase=~/\.DSK$|\.DSK\.GZ$|\.PO$|\.PO\.GZ$/).nil?
+	end
 	DSK_FILE_LENGTH=143360
 	attr_accessor (:file_bytes)
 	# does this DSK have a standard Apple DOS 3.3 VTOC?
 	def	is_dos33?
 		# VTOC is at offset 0x11000
 		# bytes 1/2/3 are a track number, sector number and DOS version number
 		# see if these are reasonable values
 
 		(@file_bytes[0x11001]<=34) && (@file_bytes[0x11002]<=15) && (@file_bytes[0x11003]==3)
 	end
+
 
 	#create a new DSK structure (in memory, not on disk)
 	def initialize(file_bytes="\0"*DSK_FILE_LENGTH)	
 		if (file_bytes.length!=DSK_FILE_LENGTH) then
 			raise "DSK files must be #{DSK_FILE_LENGTH} bytes long (was #{file_bytes.length} bytes)"